package Demo04;

public class Circle  {

    public static final double PI = 3.14;


    private final double radius = 10;


    public double area() {
        return PI * radius * radius;
    }


    public static void main(String[] args) {
        Circle circle = new Circle();
        System.out.println("圆的面积为: " + circle.area());
    }
}
